Diabetes is a chronic disease due to deficiency in the production of insulin by the pancreas or ineffectiveness of the insulin produced. The disease results in increased levels of glucose in the blood and then causes damages to many of the body's tissues or organs, in particular the blood vessels and the nerves.
There are two forms of diabetes, type I diabetes and type II diabetes. Type I diabetes is also called insulin-dependent diabetes mellitus (IDDM). The IDDM patients have destruction of pancreatic beta cells which causes failure to produce insulin and is vital to the patient's life. Type I diabetes develops frequently in children and adolescents, and therefore was previously known as juvenile diabetes. However, it is being now increasingly noted in adults. Type I diabetic patients must administer insulin by injection for their entire life time. Type II diabetes, also called non-insulin-dependent diabetes mellitus (NIDDM), is strongly familial; however, environmental factors also play an important role in the development of the disease. Healthy diet, physical exercise and avoidance of overweight may prevent the disease and control its progress. Type II diabetic patients need to take medicaments for satisfactory blood glucose control, and some of the patients need insulin for reducing their blood glucose levels.
Several complications are associated with diabetes, such as retinopathy, nerves damages, feet pains, varicose vein, edemas, blood circulation dysfunction, walking difficulties, liver dysfunction, hyperlcholesterolemia, proteinuria, hyperlipidemia, prostate enlargement, and hypertension. Controlling blood sugar levels will help ensure this disease under control and reduce the risk of complications.
Currently used medicaments for treatment of diabetes include sulfonylureas, meglitinides, biguanides, thiazolidinediones, and alpha glucosidase inhibitors, which however have several limitations, such as adverse effects and high rates of secondary failure. In addition, compositions comprising natural components having efficacies for treating diabetes have been reported. For example, U.S. Pat. No. 6,042,834, describes an herbal composition, comprising 15 percent by weight of dried, powdered seeds of Trigonella foenum-graecum; 23 percent by weight of dried, powdered seeds of Nigella sativa; 10 percent by weight of dried, powdered leaves of Origanum vulgare; 10 percent by weight of dried, powdered sap of Rosmarinus officinalis; 15 percent by weight of dried, powdered beans of Lupinus tennis; 12 percent by weight of dried, powdered black leaves of Lawsonia inennis; and 15 percent by weight of dried, powdered seeds of Foeniculum vulgare. Chinese Patent Publication No. 1243559 provides a herbal composition, comprising the plant of centaury (Centauri herba) 12.3% by wt., the root of dandelion (Teraxaci radix) 9.7% by wt., the fruit of juniper (Juniperi communis fructus) 6.2% by wt., the plant of nettle (Urticae herba) 7.4% by wt., the root of nettle (Urticae radix) 7.0% by wt., the root of chicory (Cichorii radix) 17.7% by wt., the leaf of black mulberry (Morus nigra folium) 7.4% by wt., the flower of yarrow (Achilleae millefolii flos) 3.5% by wt., the leaf of bilberry (Vaccinii myritilli folium) 6.6% by wt., the pod of beans (Phaseoli fructus sine semeni) 14.4% by wt., and the root of valerian (Valerianae officinalis radix) 7.8% by wt. Taiwan Patent Publication No. 201100088 discloses a multi-functional food composition with multiple components to improve hyperlipidemia, hyperglycemia and fatty liver, comprising bitter gourd, green algae, Licorice, and soybean powers. U.S. Patent Publication No. 2011159127 discloses an extract of Tonna sinensis from supercritical fluid extraction for treatments of diabetes and metabolic diseases, which is prepared by the steps of (a) drying the leaves of T. sinensis; (b) pulverizing the leaves as particles; and (c) extracting the particles with supercritical carbon dioxide to obtain the T. sinensis extract. The T. sinensis extract not only can decrease blood sugar level, but also promotes lipid degradation, inhibits the formation of huge lipid droplet and improves the metabolic symptoms.
In addition, WO2006/082481 discloses that rhizomes of Hedychium spicatum are useful for the treatment of Tinea infections. U.S. patent Publication No. 20060141069 discloses a synergistic antipyretic formulation comprising extracts of plants Berberis aristata, Tinospora cordifolia, Alstonia scholaris, Andrographis paniculata and Hedychium spicatum. Further, it has been reported that an essential oil extracted from the rhizome of Hedychium spicatum is hypoglycemic (Indian Journal of Expertmental Biology, Vol. 15, March 1977, pp. 208-219), and a mixture of the dried rhizome powder of Hedychium coronarium Koening with milk is traditionally used at some area in India to treat diabetes (J. Ethnopharmacol., 47(3): 149-158, 1995).